Telephone speaker



Nqv. 16

A. NYMAN TELEPHONE SPEAKER Filed April 27, 1922 rkon PRESSURE SOU/PC'E INVENTOR Alexander Afl/man VWITNES E ATTORNEY Patented Nov. 16, 15926.

Ul lllllED- STATES tenant drains.

ALEXANDER NYMAN, OF SWISSVALE, PENNSYLVANIA, ASSIGNOB; TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

TELEPHONE SPEAKER.

Application filed April 27,

My invention relates to improvements in sound-producing methods and instruments and it has particular reference to such instruments as employ vibratory elements.

Une object of my invention is to proivde a so-called loud speaking telephone instrument which has highly desirable operating characteristics.

Another object of my invention is to provide telephone apparatus embodying such construction as to greatly minimize or entirely eliminate the undesirable resonance eli'ects resulting from the natural period of vibration of the vibratory diaphragm common to such structures.

A more particular object of my invention is to produce sound waves by imparting a vibratory movement to a valve controlling the flow of air under pressure from an external source.

In the ordinary type of telephone apparatus employing a vibratory diaphragm, it has been found that the diaphragm may be resonant to a frequency well within the audibility range. The result of such resonance is that the intensity of vibrations of the diaphragm is greatly increased over that corresponding to non-resonant fre quencies. As can readily be seen, such effects are especially undesirable, when attempting. to reproduce sound waves from currents modulated in accordance with music, since the frequency corresponding to the resonant frequency of the diaphragm is greatly exaggerated.

According to my invention, provide telephone apparatus of such design as to substantially eliminate the above mentioned undesirable effects, all as will be explained more fully hereinafter.

With these and other objects in view, my invention further consists in the combination and in the details of construction and operation hereinafter described and claimed and illustrated in the accompanying drawing, wherein- Figure 1 is a horizontal sectional view of one form of telephone apparatus adapted to embody my invention, the section plane being indicated by the line l-I of Fig 2.

Fig. 2 is a longitudinal sectional view of the structure shown in Fig. 1, on the line In the drawing is shown a well known type of telephone receiver comprising a casmember 7 resting on the upper end of the 1922. Serial No. 556,855.

ing 1 having a cylindrical wall 2 and a base. 3 therefor adapted to form-a chamber 4 open at its upper end. The casing is constructed of insulating material, as, for example, specially treated rubber. The base 3 is provided with an opening 5 adapted to receive one end of a pipe 6 connecting the chamber 4 with a source of air under pressure (not shown) for reasons hereinafter more fully brought forth- A circular cover plate member 7, having a substantially centrally disposed perforation 8 is provided for closing the open end of the chamber 4, the edges of said plate 70 wall 2 of the casing 1. A substantially annular-shaped cap member 9 is provided with a, threaded portion 11 for engaging a similarly threaded portion'12 on the outer surface of the upper end of the wall 2 and with a shoulder portion 13 for engaging the edge of said plate member 7 which is resting upon said wall 2, whereby the cover plate member 7 may be rigidly secured in position.

A substantially circularly bent permanent magnet l t has its opposite ends 15 and 16- disposed one above the other and in alinement and is supported from the under surface of said cover plate 7 in any suitable manner. A pair of soft-iron yoke members 17 and 18, having polar project-ions 19, 21, and 22, 23, respectively, are rigidly secured to the ends 15 and 16 of the magnetizable member 14 in such manner that the polar projections of one magnet face those of the other with an appreciable air gap 2% therebetween.

A. magnetizable armature member 25 is pivotally mounted at a point 25 midway between the several polar projections in any suitable manner and is so disposed that opposite ends thereof extend through the air gap portions 2 bet-ween said polar projections. One end of the armature member 25 adjacent the poles 21 and 28 is connected to the polar projection 21 by means of a spring member 26 to admit of vibratory action of the armature member 25. The other end of the armature member 25 is rigidly secured by means of a connecting link 29, to a midpoint 27 of a relatively sti'i't vibratory plate or valve 28 which is disposed upon the upper side of the cover plate 7 immediately over the perforation 8. By 19 reason of such construction it can be seen .that vibratory action of the armature is readily transmitted to the diaphragm 28. The diameter of the diaphragm'28 is relatively large in comparison to that of the perforation 8 in the member 7, to admit ofmore perfect modulation of the air currents, as hereinafter described.

A magnetizing winding 31 is wound upon the tubular core member of a frame 32, which is so mounted between the several polar projections as to form magnetic circuits, as indicated by the arrows a, upon the passage of currents through the winding 31 in one direction. When the direction of the currents .reverses, the direction of the arrows is correspondingly reversed. Such excitation of the winding 31 is secured by connecting the terminals thereof to circuit terminals 32 and 33 embodied in the wall 2.

The adjustment of the spring 26 relative to the air pressure is preferably suchthat the air blast normally forcesthe'valve member 28 to a, raised position just above the surface of the cover plate 7,with the armature 25 centrally disposed between the several' polar projections. The general ath of the air currents may be indicated y the arrows I). These air currents, by reason of their relatively high velocity, exert but slight pressure upward on the surface of the valve member 28 ata distance radially from the opening 8. Accordingly, after the valve member is initiallylifted a slight amount from its seat, it is maintained in a definite position with reference to the cover plate 7 by the well known venturi action.

,VVhen modulating currents corresponding to a signal are caused to traverse the turns of the magnetizing winding 31, the armature member 25 is vibrated in accordance with the varying intensity of such currents and changes the flow of air between the valve plate 28 and its seat 7 The result is shown) a very loud sound. It will be noted that the undesirable effects resulting from vibratory members having a natural rate of vibration, herembefore mentioned,'are obviated in this construction.

During experimentation, it was observed that, under certain conditions, there was a tendency for the production of extraneous noises which were ascertained to be the result of the so-called organ pipe effect in the connections associating the chamber '4 with the source of air under pressure (not This difficulty. was eliminated by employing a damping substance 34, such as felt, which was disposed immediately adjacent that portion of the chamber containing the air-inlet 5 The felt is held in place by means of perforated plates 35 and 36. A thimble in the opening 5 contacts with one of these plates and a cylindrical part of the magnet 14 contacts both with the other plate and with the cover 7 so that the plates 35 and 36 are heldin place when the cover plate 7 is clamped by the cap 9.

4 While I have shown only one-embodimentof my invention, for the purpose of describing the same and illustrating its principles, it 'is apparent that various changes may be made therein without departing from the spirit of my invention. I desire, therefore, that only such limitations shall be imposed .thereon as are specifically set forth in the appended claims or demanded by the prior art.

I claim as my invention:

1. In a translating device, a member having an aperture, a cover for said aperture, means for causing 'a flow of air into said aperture of such intensity as to raise said cover from said member and to maintain it in its raised position by venturi action and means for vibrating said cover in accordance with the varying intensity of a signal.

3. In a translating device, a member having a relatively small aperture, a relatively large cover plate for said aperture, means for causing a flow of air through said aperture of such intensity as to maintain said plate by venturi action in a position out of engagement with said member and means for vibrating said member in accordance with asignal to correspondingly modify said flow of air.

' 4. A translating device comprising a casing adapted to form a chamber open at one end, said casing having a perforation, a cover plate for said chamber having a'substantially centrally disposed perforation, a plate member adapted to cover said latter perforation, means for introducing into said chamber-through said first-mentioned perforation a draft of air tending to raise said plate member and means for vibrating said neoerve sity of signal currents operatively associated with said cover plate in such manner that the latter is correspondingly vibrated.

6. In a telephone device, a casing adapted to form a chamber open at one end, a cover for said chamber having a substantially centrally disposed perforation, means for clamping said cover rigidly in position, a cover plate for said perforation, means for introducing into said chamber a draft of air of such pressure as to raise said cover plate, means for smoothing out pulsations in said draft of air caused by said latter means, a movable armature member adapted to Vibrate in accordance with the varying inten. sity of signal currents operatively associated with said cover plate in such manner that the latter is correspondingly vibrated.

7 In a telephone device, a casing adapted to form a chamber open at one end, a cover for said chamber having a substantially centrally disposed perforation, means for clamping said cover rigidly in position, a cover plate for said perforation, means for introducing into said chamber a draft of air of such pressure as to raise said cover plate, damping means tending to eliminate the socalled organ pipe effect introduced into said draft of air by said latter means, a movable armature member adapted to vibrate in accordance with the varying intensity of signal currents operatively associated with said cover plate in such manner that the latter is correspondingly vibrated.

8. In a telephone device, a casing adapted -to form a chamber open at one end, a cover for said chamber having a substantially centrally disposed perforation, means for clamping said cover rigidly inposition, a cover plate for said perforation, said casing also having a perforation, means for introducing into said chamber through said perforation a draft of air, dampin means for smoothing out pulsations in said draft of air suitably disposed about said casing perforation, and a movable armature member adapted to vibrate in accordance with the varying intensity of modulating ourrents operatively associated with said cover plate in. such manner that the latter is correspondingly vibrated.

9. Sound producing mechanism comprising a fluid chamber, means for conducting a blast of fluid thereto, damping means for eliminating the resonance effect of said conducting mcans, a valve mechanism in said chamber, said valve mechanism being of such nature that'it substantially does not inherently set up an audible vibration upon the passage of said blast, and external conforation, the diameter of said disc being great compared with its average distance from the cover plate and means for vibrat ing said disc.

12. In a telephone speaker, a chamber, means for supplying compressed air to said chamber, a cover plate closing said chamber and having a perforation therein, a disc adjacent said cover plate overlying said perforation the diameter of said disc being great compared with its average distance from the cover plate and means extending through said perforation for moving the disc toward and from said cover plate.

13. In a telephone device, a chamber means for supplying compressed air to said chamber, said chamber having a wall with an orifice therein through which the compressed air may emerge, a plate on the outer side of said wall closely adjacent thereto covering said orifice and extending beyond the edges of the orifice a distance great compared to the size of said orifice whereby the emerging air is constrained to flow in a thin sheet between said plate and said wall, the air pressure being such as to establish an equilibrium position of the plate;

14. In a telephone device, a chamber means for supplying compressed air to said chamber, said chamber having a wall with an orifice therein. through which the compressed air may emerge, a plate on the outer side of said wall closely adjacent thereto covering said orifice and extending beyond the edges of the orifice a distance great compared to the size of said orifice whereby the emerging air is constrained to flow in a thin sheet between said plate and said wall, the air pressure being such as to establish an equilibrium position of the plate and means for vibrating the plate about said equilibrium position in response to a signal.

In testimony whereof, I have hereunto subscribed my name this 18th .day of April 1922.

ALEXANDER NYMAN. 

